﻿#include <iostream>
using namespace std;
double triangleArea(const double* parray) {
	double p = (parray[0] + parray[1] + parray[2]) / 2 * 1.0;
	return sqrt(p * (p - parray[0]) * (p - parray[1]) * (p - parray[2]));
}
int main()
{
	double arr[3];
    cout << "请依次输入三条边长:";
	for (int i = 0; i < 3; i++) {
		cin >> arr[i];
	}
	
	cout<<"边长为"<<arr[0]<<"," 
		<< arr[1] << "," << arr[2]
		<<"的三角形面积:"<< triangleArea(arr);
	return 0;
}
